JP2012193765A - Electromagnetic engaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic engaging device which is adapted to prevent upsizing thereof.SOLUTION: The electromagnetic engaging device 5 includes an armature 20 attracted by a magnetic force of a magnetic coil 18 and a movable cam member 10 pushed against a rotor plate 26 by a thrust force of a cam mechanism 6. When the armature 20 and the movable cam member 10 are put in the engaged state, the movable cam member 10 can move in the same direction together with the armature 20 attracted by the magnetic coil 18. In addition, they are combined so as to prevent the thrust force of the cam mechanism 6 from being transmitted from the movable cam member 10 to the armature 20.

Description

  The present invention relates to an electromagnetic engagement device that can be switched to an engagement state that engages with an engagement target by using the thrust of a cam mechanism together with the magnetic force of an electromagnetic coil.

  As an electromagnetic clutch, the armature attracted by the electromagnetic coil comes into contact with the friction surface of the yoke, causing a differential rotation between the cam members of the cam mechanism, and the thrust of the cam mechanism accompanying the differential rotation is transmitted to the armature, There is known one in which an armature is pressed against the friction surface to maintain the engaged state (Patent Document 1).

JP 2005-263208 A

  In the electromagnetic clutch of Patent Document 1, since the thrust generated by the cam mechanism acts on the armature pressed against the friction surface of the yoke together with the attractive force generated by the electromagnetic coil, the durability and strength of the armature can withstand those forces. It is necessary to ensure. Therefore, there exists a possibility of causing the enlargement of an apparatus.

  Then, an object of this invention is to provide the electromagnetic engagement apparatus which can suppress the enlargement of an apparatus.

  The electromagnetic engagement device of the present invention is an electromagnetic engagement device that can switch to an engagement state that engages with an engagement target by using the thrust of the cam mechanism together with the magnetic force of the electromagnetic coil. And a second member pressed against the engagement target by the thrust of the cam mechanism, and the first member and the second member are switched to the engaged state. The second member together with the first member attracted by the electromagnetic coil can be moved in the same direction, and the thrust of the cam mechanism is not transmitted from the second member to the first member. (Claim 1).

  According to this electromagnetic engagement device, when the first member is attracted by the electromagnetic coil when switching to the engaged state, the second member also moves in the same direction together with the first member, but the cam mechanism is generated. The thrust is not transmitted from the second member to the first member. Therefore, the first member can be configured corresponding to the attractive force generated by the electromagnetic coil, and the second member can be configured corresponding to the thrust generated by the cam mechanism. Therefore, since the structure which can endure thrust with a suction force like the case where the 1st member and the 2nd member are comprised integrally is not required, the enlargement of an apparatus can be prevented. In addition, since the materials and structures specialized for the functions performed by the first member and the second member can be individually selected, the degree of freedom in design is improved.

  1 aspect of the electromagnetic engagement apparatus of this invention WHEREIN: It further has the engaging part provided in the state which mutually faces each of the said 1st member and the said 2nd member, The said provided in the said 1st member An engaging part may be located behind the engaging part provided in the second member in the direction in which the first member is sucked (Claim 2). According to this aspect, when the first member is sucked when switching to the engaged state, the engaging portion of the first member engages with the engaging portion of the second member, and the second member together with the first member. Can move. When the second member is moved by the thrust of the cam mechanism, the engaging portion of the second member can be separated from the engaging portion of the first member located behind the second member, so that the thrust is moved from the second member to the first member. Is prevented from transmitting to

  In one aspect of the electromagnetic engagement device of the present invention, the cam mechanism has a pair of cam members combined so as to be relatively rotatable about a common axis, and one of the pair of cam members. The cam member is provided as the second member, and the other cam member of the pair of cam members and the first member are disposed on the axis and allow the shift in the axial direction. They may be combined by spline engagement that prevents relative rotation about the axis (claim 3). According to this aspect, since the first member and the second member are arranged on the common axis with the other cam member as a reference, the positional accuracy in the radial direction between the first member and the second member is improved. Can do.

  As described above, according to the electromagnetic engagement device of the present invention, when the first member is attracted by the electromagnetic coil when switching to the engaged state, the second member also moves in the same direction together with the first member. However, since the thrust generated by the cam mechanism is not transmitted from the second member to the first member, the apparatus can be prevented from being enlarged and the degree of freedom in design can be improved.

The cross-sectional schematic diagram which showed a part of power transmission device with which the electromagnetic engagement apparatus which concerns on a 1st form was integrated. The cross-sectional schematic diagram which showed a part of power transmission device with which the electromagnetic engagement apparatus which concerns on a 2nd form was integrated.

(First form)
FIG. 1 is a schematic cross-sectional view showing a part of a power transmission device incorporating an electromagnetic engagement device according to a first embodiment of the present invention. The power transmission device 1 is mounted and used in an automatic transmission of an automobile. The power transmission device 1 has a rotating shaft 2 extending in the direction of the axis Ax, and the rotating shaft 2 is supported by the case 3 via a bearing (not shown) in a state of being rotatable around the axis Ax. The electromagnetic engagement device 5 is mounted on the power transmission device 1 as a brake device for fixing the rotating shaft 2 to the case 3 and releasing the fixing.

  The electromagnetic engagement device 5 includes a cam mechanism 6 disposed on the outer periphery of the rotating shaft 2, an electromagnetic drive unit 7 fixed to the case 3, and a friction mechanism 8 disposed between the cam mechanism 6 and the case 3. And. The cam mechanism 6 has a pair of cam members 9 and 10 combined with each other with the axis Ax as a common axis. A plurality (one in the figure) of cam balls 11 arranged in the circumferential direction are interposed between the pair of cam members 9 and 10, and the cam balls 11 are arranged in the circumferential direction formed on the cam members 9 and 10. It is held by a plurality of V-shaped grooves 12 and 13. Each V-shaped groove 12, 13 is formed in a V-shape when each cam member 9, 10 is viewed from the outside in the radial direction, and is configured such that the depth gradually decreases in the rotational direction of the rotating shaft 2. Has been.

  Of the pair of cam members 9, 10, the fixed cam member 9 located on the right side of the figure is fixed to the case 3. The other movable cam member 10 is combined with the fixed cam member 9 so as to be able to rotate relative to each of the counterpart fixed cam member 9 and the rotary shaft 2 and to move in the direction of the axis Ax. When the pair of cam members 9 and 10 change from a state in which the phases shown in FIG. 1 match to a state in which they are relatively rotated and shifted in phase, the cam ball 11 is positioned in the V-shaped groove 12 along with the relative rotation. It changes to 13 shallow positions. As a result, the cam mechanism 6 generates a thrust force that moves the movable cam member 10 away from the fixed cam member 9. The electromagnetic engagement device 5 includes a return spring 15 that urges the movable cam member 10 in a direction approaching the fixed cam member 9 in order to prevent the relative rotation of the pair of cam members 9 and 10 from occurring at the time of release. Is provided. The return spring 15 is prevented from moving in the left direction in FIG.

  The electromagnetic drive unit 7 includes an electromagnetic coil 18 and a yoke 19 that is fixed to the case 3 and holds the electromagnetic coil 18. When electric power is supplied to the electromagnetic coil 18, the electromagnetic drive unit 7 generates a magnetic field A as shown by a broken line in the figure to generate an electromagnetic force. The armature 20 disposed on the outer peripheral side of the movable cam member 10 and combined with the movable cam member 10 is attracted by the electromagnetic force. The armature 20 is spline-engaged with the inner periphery of the cylindrical portion 21 extending integrally from the yoke 19 in the direction of the axis Ax, and is prevented and positioned by a shim 22 attached to the right end of the inner periphery of the cylindrical portion 21. . By the spline engagement, the armature 20 is allowed to move only in the direction of the axis Ax, and the relative rotational movement with respect to the yoke 19 (case 3) is prevented.

  The movable cam member 10 and the armature 20 are independent members as separate parts. The movable cam member 10 and the armature 20 are combined in a state where an engaging portion 10a provided on the movable cam member 10 and an engaging portion 20a provided on the armature 20 face each other with a thrust bearing 23 interposed therebetween. The thrust bearing 23 can be omitted. The engaging portion 10a provided on the movable cam member 10 protrudes radially outward, and the engaging portion 20a provided on the armature 20 protrudes radially inward. The engaging portion 20a of the armature 20 is located behind the engaging portion 10a of the movable cam member 10 in the direction in which the armature 20 is sucked (left direction in FIG. 1). Therefore, when the armature 20 is attracted by the electromagnetic drive unit 7, the movable cam member 10 is pushed by the engaging portion 20 a, so that the movable cam member 10 moves in the same direction together with the armature 20. The armature 20 corresponds to a first member according to the present invention, and the movable cam member 10 corresponds to a second member according to the present invention.

  The friction mechanism 8 is spline-engaged with respect to the inner peripheral surface of the mounting hole 19 a formed in the yoke 19 so as to allow movement only in the direction of the axis Ax, and the radial clearance with respect to the outer periphery of the rotary shaft 2. And two rotating plates 26 as engagement objects that are spline engaged so as to allow movement only in the direction of the axis Ax with respect to the outer periphery of the rotating shaft 2. And have. One rotating plate 26 is disposed between the two fixed plates 25, and the other rotating plate 26 is disposed between the right fixed plate 25 and the movable cam member 10.

  When the movable cam member 10 moves leftward together with the armature 20 by the electromagnetic drive unit 7, a gap is generated between the cam ball 11 and the V-shaped grooves 12 and 13 of the cam mechanism 6, and the fixed cam member 9 and the movable cam member 10. And can be rotated in a differential manner. When the amount of movement (stroke amount) increases, the movable cam member 10 and the rotating plate 26 of the friction mechanism 8 start to contact each other, and the movable cam member 10 and the fixed cam member 9 are brought into contact with each other by friction caused by the contact. The cam mechanism 6 generates the thrust described above by differential rotation. Due to the thrust, the movable cam member 10 further strokes and pushes the plates 25 and 26 of the friction mechanism 8 leftward. Thus, one rotating plate 26 is sandwiched between the two rotating plates 25, and the other rotating plate 26 is sandwiched between the right fixed plate 25 and the movable cam member 10. When the pressing force of the movable cam member 10 against the rotating plate 26 increases, the frictional force generated between the fixed plate 25, the rotating plate 26 and the movable cam member 10 increases, and these are integrated at the same speed, that is, with the rotating plate 26. The rotating rotating shaft 2 is stationary with respect to the case 3. Thereby, the movable cam member 10 is switched from the released state shown in FIG.

  In this embodiment, when the movable cam member 10 is moved by the thrust of the cam mechanism 6, the engaging portion 10a of the movable cam member 10 can be separated from the engaging portion 20a of the armature 20 located behind the movable cam member 10. Is prevented from being transmitted from the movable cam member 10 to the armature 20. Each stroke amount of the movable cam member 10 and the armature 20 is set so that the movable cam member 10 is separated from the armature 20 when the stroke amount is switched to the engaged state.

  The cam mechanism 6 of this embodiment has a so-called self-locking function, and geometric conditions of the cam ball 11 and the V-shaped grooves 12 and 13 are set in consideration of torque that can be generated in the rotary shaft 2. Thus, when the electromagnetic engagement device 5 is switched from the released state of FIG. 1 to the engaged state, the engaged state is maintained without requiring an external force such as a suction force of the electromagnetic drive unit 7. When switching from the engaged state to the released state, the self-locking of the cam mechanism 6 is released by rotating the rotating shaft 2 in the reverse direction from the time of engagement while stopping energization of the electromagnetic drive unit 7. When the self-lock is released, the movable cam member 10 moves rightward by the elastic force of the return spring 15 and comes into contact with the armature 20. After the contact, the armature 20 together with the movable cam member 10 moves to the right and is switched to the released state shown in FIG. It is also possible to set the geometric condition so that the cam mechanism 6 does not have a self-locking function.

  According to the first embodiment, when the armature 20 is attracted by the electromagnetic coil 18 when switching to the engaged state, the movable cam member 10 also moves in the same direction together with the armature 20, but the thrust generated by the cam mechanism 6 Is not transmitted from the movable cam member 10 to the armature 20. Therefore, the armature 20 can be configured corresponding to the attractive force generated by the electromagnetic coil 18, and the movable cam member 10 can be configured corresponding to the thrust generated by the cam mechanism 6. Therefore, since the armature 20 and the movable cam member 10 are configured integrally, a configuration that can withstand thrust and thrust is not required, so that the apparatus can be prevented from being enlarged. Moreover, since materials and structures specialized for the functions performed by the armature 20 and the movable cam member 10 can be individually selected, the degree of freedom in design is improved.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic sectional view showing a part of a power transmission device in which an electromagnetic engagement device according to a second embodiment of the present invention is incorporated. Since this embodiment corresponds to a modification of the first embodiment, the same reference numerals are assigned to the same components as those in the first embodiment, and duplicate description is omitted. The electromagnetic engagement device 40 is mounted on the power transmission device 1 as a brake device in the same manner as in the embodiment of FIG.

  The electromagnetic engagement device 40 has an armature 41, and the configuration of the armature 41 and the mounting method thereof are different from those in the first embodiment. The armature 41 has an engaging portion 41a facing the engaging portion 10a of the movable cam member 10, and the engaging portion 41a is in the suction direction of the armature 41 with respect to the engaging portion 10a as in the first embodiment. Located behind. The armature 41 is spline-engaged so that the engaging portion 41a cannot rotate relative to the outer peripheral portion of the fixed cam member 9 around the axis Ax and is allowed to move in the direction of the axis Ax. The armature 41 is prevented from coming off in the axis Ax direction by a shim 42. Thereby, the fixed cam member 9 and the armature 41 are arranged on the common axis Ax. Since the cam members 9 and 10 of the cam mechanism 6 are combined so as to be relatively rotatable about the axis Ax, the movable cam member 10 that is the second member and the armature 41 that is the first member combined therewith are the axes. It will be arranged correctly on Ax. Thereby, the positional accuracy regarding the radial direction of the movable cam member 10 and the armature 41 can be improved.

  Further, since the armature 41 is spline-engaged with the outer peripheral portion of the fixed cam member 9, the cylindrical portion 21 (see FIG. 1) of the yoke 19 can be omitted. Therefore, the armature 41 has a shape advantageous to the magnetic path cross-sectional area as compared with the first embodiment, which contributes to the miniaturization of the yoke 19 and can be understood from the magnetic field B shown by the broken line. Therefore, the attractive force by the electromagnetic coil 18 is improved.

  The present invention is not limited to the above embodiments, and can be implemented in various forms within the scope of the gist of the present invention. In each of the above embodiments, the electromagnetic engagement device of the present invention is used as a brake device, but the present invention can also be implemented as a clutch interposed between two rotating elements.

  In each of the above embodiments, the friction mechanism 8 including the plurality of fixed plates 25 and the rotating plate 26 is employed to increase the torque capacity in the engaged state, but this embodiment is merely an example. For example, a single rotating plate 26 may be sandwiched between the movable cam member 10 and the case 3.

5, 40 Electromagnetic engagement device 6 Cam mechanism 9 Fixed cam member 10 Movable cam member (second member)
10a Engagement part 18 Electromagnetic coils 20, 41 Armature (first member)
20a, 41a Engaging portion 26 Rotating plate (engagement target)
Ax axis

Claims (3)

In an electromagnetic engagement device that can be switched to an engagement state that engages with an engagement target using the thrust of the cam mechanism together with the magnetic force of the electromagnetic coil,
A first member attracted by the magnetic force of the electromagnetic coil, and a second member pressed against the engagement object by the thrust of the cam mechanism,
When the first member and the second member are switched to the engaged state, the second member can move in the same direction together with the first member attracted by the electromagnetic coil, and the cam mechanism The electromagnetic engagement device is combined so that thrust is not transmitted from the second member to the first member. The first member and the second member further have an engaging portion provided in a state of facing each other,
The said engaging part provided in the said 1st member is located in the back of the direction in which the said 1st member is attracted | sucked with respect to the said engaging part provided in the said 2nd member. Electromagnetic engagement device. The cam mechanism has a pair of cam members combined so as to be relatively rotatable around a common axis,
One of the pair of cam members is provided as the second member,
One of the pair of cam members, the other cam member and the first member are arranged on the axis, and the spline mechanism prevents relative rotation about the axis while allowing the shift in the axial direction. The electromagnetic engagement device according to claim 1, wherein the electromagnetic engagement devices are combined together.

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